The true toll of the Ebola outbreak in the Democratic Republic of the Congo remains cloudy as rebel-held parts of the country remain off-limits to health workers, despite the World Health Organisation reporting a decline in cases.

AID agencies say the Ebola outbreak in Democratic Republic of Congo could be tipping into a wider crisis as the number of new cases spiked and violence grounded health workers for a second time.

The outbreak is centred in the city of Beni, where rebels killed at least 18 people in an attack last month, forcing health workers to suspend operations for several days.

Community resistance has also caused violence, with angry villagers attacking Red Cross volunteers on several occasions and preventing a burial last week.

The outbreak is expected to last at least another three or four months but if insecurity continues there could be “a much larger wave building,” said Peter Salama, emergency response chief of the World Health Organisation, on Thursday.